Nickel is a biologically active trace metal important to mammalian health, as are numerous obligately anaerobic bacteria which inhabit the microintestinal environment. The proposed study centers on further resolving i) the biochemical/biological nature of nickel in acetogenic bacteria, and ii) the autotrophic metabolism of this biological group. Specifically, we plan to continue our studies on the biochemistry and physiological function of the nickel enzyme, carbon monoxide dehydrogenase, and to characterize acetogenic hydrogenase. Further analyses on the regulation of these enzymes will yield insights into their physiological roles, and antibodies (rabbit) against these catalysts will be used as specific probes to aid in this elucidation. Additionally, purification of recently discovered metallo nickel proteins (currently of unknown function) will be undertaken, as will studies on nickel transport and the genetics of acetogenic bacteria. A recently developed minimally defined medium will facilitate this latter work. Since acetogens are obligate anaerobes and are sensitive to oxidation, anaerobic cultivation and purification procedures will be utilized throughout the investigation.